1. Technical Field
The present invention relates to a waste ink liquid absorber and inkjet-type recording apparatus including the same.
2. Related Art
In the inkjet-type recording apparatus, flushing was performed for the purpose of preventing an injection nozzle of a recording head from being dried. It is an operation of blank injection of an ink from the injection nozzle independent of recording-controlling signals. Moreover, in the case that the injection nozzle is blocked, a so-called cleaning operation is performed wherein the injection nozzle of the recording head is sealed with a capping means and an ink is compulsorily discharged from the injection nozzle by means of a suction means connected to the capping means. The ink not used for recording and injected from the injection nozzle by these flushing and cleaning was received by the capping means and was conveyed as a waste liquid into a waste liquid tank provided on the inkjet-type recording apparatus by the suction means. Moreover, in margin-less printing, the ink injected to the outside of a recording medium was conveyed to the waste liquid tank via a trapping material provided on a platen.
For example, FIG. 8 shows an inkjet-type recording apparatus equipped with a waste liquid tank for the waste ink derived from the above flushing and cleaning. FIG. 8 is a partial perspective view of the inkjet-type recording apparatus 10 and particularly shows the structure of a printing part 40 and an ink waste liquid-conveying part 70. The printing part 40 has, for example, a carriage 42 on which an ink cartridge is placed, a printing head 44 injecting an ink, a shaft hole 46 provided on the cartridge 42, and a guide shaft 48 which is passed through the shaft hole 46 and slidably supports the carriage 42 in the almost vertical direction toward a feeding direction. The recording head 44 has a plurality of the ink injection nozzles arranged along the feeding direction of the article to be recorded. The printing part 40 further has a timing belt 402, a carriage motor 404, a black ink cartridge 406, and a color ink cartridge 408.
When the carriage motor 404 drives the timing belt 402, the carriage 42 reciprocates almost perpendicularly to the feeding direction of the article 11 to be recorded under a guide of the guide shaft 48. On the side of the carriage 42 opposite to the article to be recorded, a recording head 44 including an injection nozzle for the black ink and an injection nozzle for color inks are mounted. On the upper part of the carriage 42, the black ink cartridge 406 and the color ink cartridge 408 which feed inks to the recording head 44 are detachably mounted.
The inkjet-type recording apparatus 10 is further equipped with the ink waste liquid-conveying part 70 which conveys the ink discharged from the recording head 44 as a waste liquid and a wiping means 80. The ink waste liquid-conveying part 70 has the capping means 72 which seals the injection nozzle of the recording head 44. Furthermore, the ink waste liquid-conveying part 70 has a tube 74 connecting the injection nozzle of the recording head 44 to the capping means 72 and a pump 76 which conveys the ink present inside the tube 74 with elastically deforming a part of the tube 74. The ink waste liquid-conveying part 70 further has a waste liquid tank 100 which accumulates the ink conveyed by the pump 74. The capping means 72 of the ink waste liquid-conveying part 70 is placed at a non-recording region (home position) outside the recording region (feeding pathway of the article 11 to be recorded). The article 11 to be recorded is conveyed by a conveying roller (not shown in the figure) or a discharging roller 52. The wiping means 80 has an elasticity and is placed in the vicinity of the edge part at the recording region side of the capping means 72.
When the inkjet-type recording apparatus 10 having the above constitution does not perform printing, the carriage 42 is moved from the recording region to the non-recording region (home position). When the recording head 44 provided on the carriage 42 is moved just above the home position, the capping means 72 is elevated to the carriage 42 side and the surface having the injection nozzle of the recording head 44 can be sealed.
When the capping means 72 seals the surface having the injection nozzle of the recording head 44, drying of the injection nozzle of the recording head 44 can be suppressed. Moreover, the capping means 72 can receive a blank-injected ink by actuating the flushing operation wherein ink drops are blank-injected from the recording head 44. The flushing is carried out by applying a driving signal irrelevant to recording.
In the state that the capping means 72 seals the recording head 44, an ink is compulsorily sucked and discharged from the recording head 44 by sucking the air in an inner space formed with the recording head 44 and the capping member 72 using the pump 76. By compulsorily sucking and discharging the ink from the injection nozzle of the recording head 44, the recording head 44 is cleaned and the blocking of the injection nozzle is dissolved.
When the carriage 42 returns from the non-recording region to the recording region, it first secedes from the capping means 72. Furthermore, as the carriage 42 moves to the non-recording region side, the wiping means 80 advances onto the moving pathway of the recording head 44 to wipe the ink on the nozzle-forming surface of the recording head 44.
The ink received by the capping means 72 by the above cleaning, flushing, and the like is sucked by the pump 76 of the ink waste liquid-conveying part 70 and is transferred, via the tube 74 whose one end is connected to the capping means 72, to the waste liquid tank 100 which is connected to another end of the tube 74.
When the waste liquid tank 100 is tightly sealed, drying of the waste ink is inhibited and the waste liquid tank is filled with the waste ink in a short period, so that it is difficult to hold an expected amount of the waste ink. On the other hand, when the tank is formed as a tray-like vessel with opening the upper surface of the waste liquid tank in order to enhance the amount of the waste ink to be held, the ink may be scattered by the vibration of the inkjet recording apparatus 10 during recording or the ink may flow out when the inkjet recording apparatus 10 is slanted. Thus, in general, an absorber which absorbs the waste ink is stored in the waste liquid tank 100.
Moreover, the waste liquid tank 100 has an ink-reserving part (i.e., waste ink-diffusing chamber) and an absorber placed at surrounding area of the ink-reserving part (i.e., absorber-holding chamber). After the waste ink conveyed from the tube 74 is reserved in the waste ink-diffusing chamber, the waste ink is absorbed from an absorbing surface of the absorber. However, among the components contained in the waste ink liquid, a colorant component is difficult to absorb as compared with a solvent component and a water component. Particularly, in a pigment ink wherein the coloring component of the ink is a pigment, only the solvent component and water component permeate inside the absorber and the pigment particles tend to deposit on the surface of the absorber.
In an aqueous pigment ink, there has been developed an aqueous pigment ink containing a water-insoluble dispersible polymer (e.g., Document 2) mainly for the purpose of improving coloring properties on standard paper (e.g., Document 1) and both of coloring properties and glossiness on standard paper. Moreover, various improvements have been proposed on the structure of the waste liquid tank of the inkjet recording apparatus and, for example, a technology of slanting the bottom of the waste ink-diffusing chamber of the waste liquid tank is known (e.g., Document 3).
[Document 1] JP-A-2005-15765
[Document 2] JP-A-2004-75988
[Document 3] JP-A-2004-34361
In the inkjet recording apparatus using the aqueous pigment ink described in the above Documents 1 and 2, there has been generated a phenomenon that the waste ink is more difficult to absorb into the absorber in the waste ink tank as compared with a conventional pigment ink. Specifically, in the pigment particles dispersed by the water-insoluble polymer, there is a tendency that only the solvent component and water component permeate inside the absorber and the pigment particles are apt to deposit on the surface of the absorber, as compared with conventional pigment particles. Furthermore, since the waste ink discharged from the waste liquid tube into the waste ink-diffusing chamber in the waste ink tank foams, it is further difficult to absorb the ink into the absorber when the foam remains. Finally, since the waste ink is deposited inside the waste liquid tube, flushing and cleaning cannot be carried out even when a sufficient absorbing ability remains in the absorber itself.